stevens



3O 1 i fuel valve.

JOHN STEVENS, OF ST. PAUL, MINNESOTA.

CARBURETEB.

Specification of Letters Patent. Patented lvlay 2'? 1919 Application filed November 9, 1917. Serial No. 201,086.

I To all whom it may concern:

Be it known that I, JOHN W. STEVENS, a citizen of the United States, resident of St. Paul, county of Ramsey, State of Minnesota, have invented certain new and useful Improvements in Carbureters, of which the following is a specification.

The object of my invention is to improve the carbureter shown and described in Letters Patent of the United States issued to me May 30, 1916, No. 1,184,889. In this patent provision was made for increasing the effective area of the suction ports through which the mixture passes to the cylinders for increasing the speed of the engine and also increasing the auxiliary or variable air ports but in less proportion for the purpose of providing an increase in the suction at the nozzle.

The object of my present invention isto provide improved means in connection with the feed of the fuel for increasing the supply and the volume of the mixture proportionately with the increase in the primary air intake openings, thereby maintaining a f proper balance or uniformity in the fixed volume of air and the quantity of fuel.

A further object is to provide improved means for eifecting this increase in the fuel supply without changing the position of the The invention consists generally in various constructions and combinations, all as hereinafter described and particularly pointed out in the claims.

In the accompanying drawings forming part of this specification,

Figure 1 is a vertical sectional view through a carbnreter embodying my invention,

Fig. 2 is a detail view of the plug or stem having the seat therein for the needle valve by which the feed of the fuel is controlled,

Fig. 3 is a detail view of the cylinder throttle valve, showing the arrangement of the ports therein,

Fig. 4; is a detail sectional view of a modified construction of the fuel controlling stud.

In the drawing, 2 represents a casing hav- 1 ing a fuel chamber or reservoir 3 communicatingthrough a passage l and a valve 5 with a source of fuel supply, not shown. The movement of the valve is controlled by the usual float 6 which encircles an inner casing or shell 7 between which and the walls of the casing 2 the reservoir is formed. The casing 2 has a removable top 8 to allow access to a chamber 9 within the casing 7 through the open top 10 of said chamber. From this chamber a passage 11 leads to the engine cylinder, not shown. In the base of the casing 7 is a hydro-carbonfuel duct 12 communicating with the chamber 3 and with a nozzle 13 which projects up into the chamber 9 and is provided with a needle valve 1i by'means of which the fiow of fuel through the nozzle is controlled in the usual way.

Within the casing 7 I provide a cylindrical member 15 having an annular flange 16 that is seated in the wall of the casing 7 near the middle portion thereof and separates the lower portion of this chamber from the upper portion. This member 15 is provided below said flange with variable air intake ports 17 extending vertically therein at intervals and spaced apart and communicating with the lower portion of the chamber 9 and with the open air through the passage 18, across which the duct 12 extends. Above the flange 16 suction ports 19 are formed in said cylindrical member. These ports 17 and 19 have preferably parallel longitudinal edges and converging end edges so that the openings gradually increase in area from one longitudinal edge to the opposite edge and the ports are oppositely arranged; that is, the ends converge in one direction in the upper group of ports and in the opposite direction in the lower group of ports, and as the openings in the upper ports increase in effective area through the movement of the throttle, the ports in the lowergroup will also increase but in less proportion.

Fitting within the cylinder15 is a hollow stationary member 20, preferably in the form of a truncated cone, having a flange 21 seated'against the lower end of the cylinder 15, the fuel supply nozzle 13 projecting upwardly into said member and terminating beneath and near air intake ports 22 provided in the upper portion of said'stationary member. The cylinder 15 and the member 20 are normally stationary and the ports 22 admit the fuel mixture to the space within the cylinder 15. Within this cylinder 15 I provide a throttle valve 23, cylindrical in form, seated at its lower end on the flange 21 and having ports 24 above the flange 16 and similar ports 25 below the flange 16 adapted to register respectively with the ports 19 and 17 in the stationary cylinder15.

The valve 23 has a stem 26 provided with a lever 27 that is actuated by an arm 28 on a rock shaft 29 that is operated through a suitable mechanism extending to the drivers seat.

The cylinder 23 constitutes in effect the throttle of the engine, for by rotating it the driver can increase or decrease the area of the air ports in the cylinder 15 according to the atmospheric conditions or the load on the engine. A stop pin 30 may be provided on the inner cylinder, adapted to enter a notch 31 in the cylinder 15 and limit the rotating movement of the inner cylinder. The suction ports 19 will be partially open even when the throttle is rotated and entirely close the air ports 17 and owing to the difference in shape of these ports, the movement of the throttle in one direction to increase the area of the suction ports will, while increasing the width of the opening inthe air ports 17, at the same time reduce their length and the proportion of increase in area in the ports 17 will therefore be less than in the suction ports and the depression around the nozzle will be increased and the feed of the fuel quickened, all as particularly set forth in my patent above referred to.

For the purpose of regulating the fuel in take opening proportionately with the variation in the effective area. of the air openings, I provide a stud 32 having an end rectangular in cross section and fitting within a socket 33 in the lower end of the stem 2.6. The stud 32 has a recess 34 in its lower end and is exteriorly threaded to engage the interiorly threaded surface of the nozzle 13, and in the bottom of said recess a valve seat 35 is provided for the needle valve 14, with a duct 36 leading therefrom to ports 37 in the walls of said duct and through which fuel supply is drawn to mingle with the air. The stud 32 is mounted to revolve with the stem 26 and as this stem is operated to vary the effective area of the air intake openings, the valve seat in the lower end of said stud 32 will be moved away from or toward the normally stationary needle valve so that when the area of the air intake openings is changed, a corresponding change will be made in the fuel opening and the volume of fuel proportionately increased or decreased. I thereby am able to maintain a proper balance in the carbureter between the fuel supply and the volume of air admitted for the mixture.

In Fig. 4 I have shown a modified construction of the stud which consists in providing an elongated duct 34' in place of the recess 34: and the duct 36. The duct 34: has the seat for the needle valve in its lower end and has the function of offering a greater resistance to the flow of fuel than the shorter duct, where the valve seat is located adjacent to the ports 37. I do not, however, confine myself particularly to this construction, as the length of the duct may be modified to suit different conditions and as experiment may determine the most suitable distance of the valve seat from the ports to obtain the greatest efficiency.

I prefer to provide worm threads 32 on the lower end of the studs of both constructions, fitting corresponding threads provided in the upper end of the supply nozzle 13. The purpose of this is to obtain a quick vertical movement of the stud with a compa-ratively limited rotation to open or close quickly the needle valve port.

I claim as my invention 1. A carbureter comprising a casing having inlet and outlet openings and a nozzle projecting through said inlet opening, concentric, relatively movable members mounted within said casing and having groups of ports opened or closed by the movement of one of said members, one of said members having an opening therein to receive said nozzle, a normally stationary needle valve mounted in said nozzle, a stud having its lower end tapped into said nozzle for quick vertical movement therein and provided with a recess and a seat in the bottom of said recess for said needle valve, and ports leading outwardly from said seat and communieating with the ports of said members, said stud having means for connection with one of said relatively movable members to operate simultaneously therewith for moving its valve seat toward or from said needle valve to increase or decrease the fuel supply proportionately with, the variation in the effective area of said ports. 7

2. A carbureter comprising a casing having inlet and outlet openings and a nozzle projecting through said inlet opening, concentric, relatively movable members mounted within said casing and having groups of ports opened and closed by the movement of one of said members, one of said members having an opening therein to receivesaid nozzle, a member encircling said nozzle and provided with ports, the movement of one of said concentric members in. one direction increasing the area of the groups of ports and increasing the area of one group in less proportion, a normally; stationary needle valve projecting into said nozzle, a stud mounted in said nozzle and having a passage and ports leading thereto, and a seat for said needle valve, said stud projecting upwardly through said encircling member and one of said. relatively movable members having a stem depending therethrough and provided with a socket to receive the upper end of said stud, rotation of:said stem imparting a corresponding movement to one of said relatively movable members and to said stud to move its seat toward or from said needle valve and increase or decrease the fuel supply opening proportionately with the increase or decrease in the efl'ective area of the groups of ports.

3. A carbureter comprising a casing having inlet and outlet openings and a nozzle projecting through said inlet opening, concentric, relatively movable members mounted within said casing and having groups of ports opened or closed by the movement of one of said members, one of said members having an opening therein to receive said nozzle, a needle valve mounted in said nozzle, a stud having an exteriorly threaded lower end fitting within the open upper end of said nozzle, said stud having a recess in copies of this patent may be obtained for its lower end and provided with a seat for said needle valve in the bottom of said recess and also having laterally extendlng ports above said seat and a duct leading from said seat to said ports, said stud having means for connection with one of said relatively movable members to operate simultaneously therewith for moving its valve seat toward or from said needle valve to increase or decrease the fuel supply proportionately with the variation in the efiective area of said ports.

In witness whereof, I have hereunto set my hand this 31st day of October, 1917 JOHN W. STEVENS.

five cents each, by addressing the commissioner of Patents, Washington, D. 0." 

